Genetic Analysis and QTL Mapping of Seed Coat Color in Sesame (Sesamum indicum L.)

Abstract

Seed coat color is an important agronomic trait in sesame, as it is associated with seed biochemical properties, antioxidant content and activity and even disease resistance of sesame. Here, using a high-density linkage map, we analyzed genetic segregation and quantitative trait loci (QTL) for sesame seed coat color in six generations (P1, P2, F1, BC1, BC2 and F2). Results showed that two major genes with additive-dominant-epistatic effects and polygenes with additive-dominant-epistatic effects were responsible for controlling the seed coat color trait. Average heritability of the major genes in the BC1, BC2 and F2 populations was 89.30%, 24.00%, and 91.11% respectively, while the heritability of polygenes was low in the BC1 (5.43%), in BC2 (0.00%) and in F2 (0.89%) populations. A high-density map was constructed using 724 polymorphic markers. 653 SSR, AFLP and RSAMPL loci were anchored in 14 linkage groups (LG) spanning a total of 1,216.00 cM. The average length of each LG was 86.86 cM and the marker density was 1.86 cM per marker interval. Four QTLs for seed coat color, QTL1-1, QTL11-1, QTL11-2 and QTL13-1, whose heritability ranged from 59.33%–69.89%, were detected in F3 populations using CIM and MCIM methods. Alleles at all QTLs from the black-seeded parent tended to increase the seed coat color. Results from QTLs mapping and classical genetic analysis among the P1, P2, F1, BC1, BC2 and F2 populations were comparatively consistent. This first QTL analysis and high-density genetic linkage map for sesame provided a good foundation for further research on sesame genetics and molecular marker-assisted selection (MAS).

Inheritance of seed coat color in sesame

“…According to most of the previous studies on the inheritance of sesame seed coat color, this trait is determined by major genes at the embryo (Gutiérrez et al, 1994;Ashri, 2006;Falusi, 2007;Zhang et al, 2013). Although these reports did not present results of reciprocal crosses, it is possible to conclude that there was segregation for F 2 , which discards the maternal effect.…”

“…Gutiérrez et al (1994), Falusi (2007), and Zhang et al (2013) concluded that inheritance was controlled by major genes at the cell nucleus. Shim et al (2005) and Ashri (2006) reported that minor genes were the ones responsible for this trait; however Ashri (2006) also observed that the white color was a recessive character.…”

Descripción de semillas silvestres de Euphorbia strigosa Hook and Arn del estado de Nayarit, México

“…In the black lines of Phaseolus vulgaris the protein content, iron and zinc are higher, in lines of other colors are richer in calcium, while the "carioca" is high in magnesium and manganese (Silva et al 2012). For the case of sesame, color is an important aspect as it is associated with biochemical properties, antioxidants and resistance to diseases (Zhang et al 2013). In Brassica juncea the yellow color was found in the genotype of the mother, and brown the father, the latter being the dominant (Xu et al 2010).…”

CHARACTERIZATION OF SOME INDIAN SESAME (Sesamum indicum L.) CULTIVARS THROUGH SOLUBLE SEED STORAGE PROTEIN MARKERS

“…Similarly, Singharaj & Onsaard (2015) carried out SDS-PAGE in sesame genotypes with varied seed coat colour, for its food value. According to recent study, seed coat colour in sesame is more helpful in phylogenetic study than geographic origin of genotypes (Zhang et al, 2013).…”

“…Correlation of protein markers with seed coat colours would further help in assessing genotypes for those biochemical traits which are linked to particular seed coat colours (Zhang et al, 2013). Such correlation, if exists, can be employed to identify diverse and superior sesame genotypes for future crop improvement programme.…”